[knightwalker]

Hello everyone,


I have a big problem with the function "AddLayer" in SnappyHexMesh. I tried several parameters but the layers don't appear in ParaView, even if the calculation takes them into account. I increased the number of layers, the number of iterations... but nothing work, except a very few layers (picture).



Can someone help me please ? Thank you.

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.0                                   |
|   \\  /    A nd           | Web:      http://www.openfoam.org               |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version         2.0;
    format          ascii;
    class           dictionary;
    object          snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// Which of the steps to run
castellatedMesh true;  // true;
snap            true;  // true;
addLayers    true; // true;

geometry {
    wall.stl {type triSurfaceMesh; name wall;}
    sphere3 {type searchableSphere; centre (0 0 0); radius 500;}
    sphere4 {type searchableSphere; centre (0 0 0); radius 1000;}
};

// Settings for the castellatedMesh generation.
castellatedMeshControls {
maxLocalCells 1000000;
maxGlobalCells 10000000;
minRefinementCells 5;
nCellsBetweenLevels 2; //6
refinementSurfaces {
  wall {
   level (2 3); //level (3 4)
  }
}
refinementRegions {
   sphere3 {
    mode inside;
    levels ((500 3)); 
    }
   sphere4 {
    mode inside;
    levels ((800 2)); 
    }
 }
resolveFeatureAngle 20;
locationInMesh (0 500 0);
features (
  {
    file "wall.eMesh"; level 3;
  }
);
allowFreeStandingZoneFaces false;
}

// Settings for the snapping.
snapControls {
nSmoothPatch 4;
tolerance 10;
nSolveIter 80;
nRelaxIter 8;
}

// Settings for the layer addition.
addLayersControls {
relativeSizes true;
layers{
     wall
        {
            nSurfaceLayers 8;
        }
}
expansionRatio 1.2;
finalLayerThickness 0.3;
//thickness 100;
minThickness 0.005;
nGrow 0;
featureAngle 30;
nRelaxIter 5;
nSmoothSurfaceNormals 1;
nSmoothNormals 3;
nSmoothThickness 10;
maxFaceThicknessRatio 1.0;//0.5
maxThicknessToMedialRatio 1.0;//0.3
minMedianAxisAngle 130;
nBufferCellsNoExtrude 0;
nLayerIter 50;

}

// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls {
maxNonOrtho 70;
maxBoundarySkewness 20;
maxInternalSkewness 4;
maxConcave 80;
minFlatness 0.5;
minVol -1e13;
minArea -1;
minTwist 0.05;
minDeterminant 0.001;
minFaceWeight 0.05;
minVolRatio 0.01;
minTriangleTwist -1;
nSmoothScale 4;
errorReduction 0.75;
minTetQuality 1e-30;
}

// Advanced
// Flags for optional output
// 0 : only write final meshes
// 1 : write intermediate meshes
// 2 : write volScalarField with cellLevel for postprocessing
// 4 : write current intersections as .obj files
debug 0;

// Merge tolerance. Is fraction of overall bounding box of initial mesh.
// Note: the write tolerance needs to be higher than this.
mergeTolerance 1E-6;

// ************************************************************************* //

Capture du 2019-03-25 15-38-59.jpg


Capture du 2019-03-25 17-31-27.jpg

[knightwalker]

Up ^^ guys

[knightwalker]

Up the topic

[chegdan]

Layers are most easily added in regions where near wall cells have an aspect ratio of unity. It looks like your near surface cells have a really large aspect ratio.

[knightwalker]

Hi chegdan, you are right, I understood the problem this morning and I fixed it ! Now I have layers around all my surface ^^.